Ryunosuke Uranishi

Early-onset tolerance in rat global cerebral ischemia induced by a mitochondrial inhibitor

It was studied whether a subtoxic dose of the mitochondrial neurotoxin, 3-nitropropionic acid (3-NPA), can initiate early-onset tolerance induction for subsequent ischemic injury. Wistar rats were pretreated for 3 h by intraperitoneal 3-NPA (20 mg/kg body weight; n=13) or solvent (n=12). Fifteen minutes global cerebral ischemia was induced by bilateral carotid artery occlusion and hypobaric hypotension. rCBF and tissue hemoglobin oxygen saturation were measured by laser Doppler scanning and a microspectrophotometric method. Ischemic insult and brain temperature were identical in both groups. Body weight and neurological scores recovered in the pretreated group but further deteriorated in the non-treated group (P<0.05). Quantitative histology demonstrated a better neuronal density in neocortex and hippocampal CA2, CA3, and CA4 of pretreated animals (P<0.05).

Evaluation of Absolute Cerebral Blood Flow by Laser-Doppler Scanning – Comparison with Hydrogen Clearance

A major limitation of laser-Doppler (LD) flowmetry, which enables noninvasive and continuous recording of tissue perfusion, is its inability to evaluate the absolute cerebral blood flow (CBF). Using a computer-controlled micromanipulator, the LD scanning technique provides information on the brain microcirculation in many different locations, information which is not available from a single stationary probe. The purpose of the current study was to examine whether LD scanning estimates can be calibrated for the absolute CBF by comparing LD scanning with the hydrogen clearance (HC) method. In Wistar rats (n = 31) including old rats (122–123 weeks old, n = 8), the CBF was altered using the global ischemia model by bilateral carotid artery occlusion coupled with hypobaric hypotension. The CBF was determined simultaneously by the LD scanning technique and HC at each mean arterial blood pressure step, and the correlation of CBF between the two techniques was analyzed. CBF measured by LD scanning was expressed as LD units. Absolute CBF values obtained by methods were correlated (r = 0.87), and the formula to calibrate absolute CBF values from LD units was y = 1.8x – 0.6. On the other hand, in old rats the formula to calibrate the absolute values was different (y = 1.3x + 8.3, r = 0.85). The results suggest that CBF data obtained by LD scanning could be calibrated into absolute blood flow values in particular circumstances, and that LD scanning could compensate in part for the weakness of LD flowmetry.

Expression of ciliary neurotrophic factor (CNTF), CNTF receptor alpha (CNTFR-α) following experimental intracerebral hemorrhage in rats

Ciliary neurotrophic factor (CNTF) is known as a neuro-survival factor in the developing and developed CNS, as well as in the CNS following injury. However, little is known about the expression of CNTF or that of its receptor (CNTFR-alpha) in cases of intracerebral hemorrhage (ICH). We investigated the temporal and spatial profiles of CNTF and CNTFR-alpha expression using a collagenase-induced ICH rat model. CNTF expression was up-regulated from the day following ICH induction and reached a peak level at 5 to 14 days, with increased expression observed in brain tissue surrounding the hematoma lesion and white matter structures in association with astroglial proliferation. Further, CNTFR-alpha was transiently expressed in the cerebral cortex surrounding the hematoma, with a peak at 5 days. Administration of exogenous CNTF into the lesion following initiation of ICH resulted in a prolonged expression of CNTFR-alpha on cortical neurons neighboring the hematoma. Our findings suggest differential regulation of CNTF and CNTFR-alpha, and the possibility of a therapeutic strategy using CNTF administration for ICH.

Color Doppler Flow Imaging of the Superior Ophthalmic Vein in Dural Arteriovenous Fistulas

Background and Purpose— This article evaluates the intracranial venous hemodynamics of dural arteriovenous fistula (DAVF) on the basis of data from color Doppler flow imaging (CDFI) findings of the superior ophthalmic vein (SOV) and discusses the clinical application of the SOV CDFI to the DAVFs. Methods— We examined the diameter, flow direction, flow waveform, and flow velocity of the SOV using CDFI in 20 patients with intracranial DAVF. Six patients were asymptomatic; the other 14 patients were symptomatic. Angiographic retrograde cortical venous filling was seen in 14 patients. Results— In the DAVFs, the average SOV diameter was 2.95±1.15 mm, which was significantly broad compared with that of the control subjects (P <0.05). The flow direction was reversed in 2 patients and normal in the other 18 patients. Three patients showed an abnormal waveform. A reversed pulsatile waveform was observed in 2 patients, and a normograde pulsatile waveform was seen in 1 patient. The other 17 patients showed normal waveform. The average SOV diameter and resistance index values were significantly higher (P <0.05) in patients with clinical symptoms, angiographic retrograde cortical venous fillings, or large DAVFs compared with those in the other patients. Conclusions— The SOV CDFI findings in DAVFs correlated well with the patient’s clinical symptoms, angiographic findings, and DAVF size. These findings were useful to evaluate the intracranial venous hemodynamics in DAVFs.

Extensive cervical laminoplasty for patients with long segment OPLL in the cervical spine : An alternative to the anterior approach

We investigated treatment of long segment cervical OPLL by posterior decompression using a laminoplasty technique. Our aim was to both decompress the spinal cord and also to preserve neck motion. There were 38 patients treated by this posterior approach. Twenty-eight patients underwent C1-C7 expanding laminoplasty, 4 patients underwent C1-T1 expanding laminoplasty, and 6 patients C2-C7 expanding laminoplasty. The transverse width of the open-door laminoplasty was sufficient to achieve decompression of not only the spinal cord but also the nerve root outlets at each laminoplasty level. There were no complications related to this surgical technique, nor late deterioration in the mean follow up period of 4. 5 years. We propose expanding laminoplasty as an important option for the treatment of long segment cervical OPLL.

Effect of carotid endarterectomy on the ophthalmic artery.

Summary.Summary. Background: To evaluate the effect of carotid endarterectomy on ophthalmic artery flow direction and peak systolic flow velocity, the authors examined the ophthalmic artery on 32 patients who had undergone carotid endarterectomy. Methods: The 32 patients had more than 70% stenosis of the internal carotid artery at its origin on angiography. The ophthalmic artery ipsilateral to the carotid endarterectomy was evaluated by the ophthalmic artery color Doppler flow imaging before surgery and then at one week, one month, and three months after surgery. Findings: (1) Before carotid endarterectomy: eight patients showed reversed ophthalmic artery direction. In the other 24 patients with antegrade ophthalmic artery flow direction, the average peak systolic flow velocity was 0.17±0.10 m/sec. (2) At one week after carotid endarterectomy: The reversed ophthalmic artery flow direction was resolved in each patient. The average peak systolic flow velocity in the patients with preoperative antegrade flow rose significantly to 0.28±0.10 m/sec (p<0.05). (3) At one month and three months after carotid endarterectomy: All patients showed the antegrade ophthalmic artery flow direction. The average peak systolic flow velocities showed no significant change compared to the value at one week after carotid endarterectomy. (4) During the followed up period, there was no patient showing worsening or recurrence of clinical symptoms including the visual symptoms. Interpretation: Carotid endarterectomy brought about the correction of the reversed flow and an increase in the peak systolic flow velocity of the ipsilateral ophthalmic artery immediately after surgery.

Effects of Bypas's on CO2 Cerebrovascular Reactivity in Ischaemic Cerebrovascular Diseases – Based on the Intra-Operative LCBF and CO2 Cerebrovascular Reactivity Studies

Summary The authors evaluated the effects of superficial temporal to middle cerebral artery (STA-MCA) bypass on CO2 cerebrovascular reactivity (CVR) in ischaemic cerebrovascular diseases (CVDs). Local cerebral blood flow (LCBF) and CO2 CVR in 19 patients with ischaemic CVD subjected to standard STA-MCA bypasses were examined during surgery. Single photon emission computed tomography (SPECT) with acetazolamide (ACZ) activation was also performed before and at 1 month after surgery. The results are as follows. 1) Before bypass, the average CO2 CVR value was −1.50±2.30%/mmHg (mean±SD). SPECT showed disturbed response to ACZ in all cases. Fifteen cases showed the steal phenomenon. After bypass, the mean CO2 CVR value significantly (p<0.05) increased, and four cases resolved their steal phenomenon. 2) Before bypass, the mean LCBF was significantly (p<0.05) lower than the control level. After bypass, the mean LCBF significantly (p<0.05) increased. 3) In the postoperative SPECT findings, 13 cases showed a disturbed response to ACZ. The CO2 CVR value in these 13 cases was −1.21±1.19%/mmHg, which was significantly (p<0.05) low compared to the values for the 6 cases showing normal postoperative ACZ responses. In ischaemic CVDs before bypass, the CO2 CVR values were extremely low. After bypass, however, CO2 CVR and LCBF values significantly improved. SPECT findings, including ACZ challenge, correlated well to the LCBF and CO2 CVR values. STA-MCA by pass exerted a favourable effect on the CO2 CVR and LCBF values immediately after bypass in the cases showing a reduced pre-operative response to CO2.

Brain metastases from urachal carcinoma

We present a case of brain metastases of the urachal carcinoma, which is extremely rare and malignant. Contrast-enhanced MRI was employed to detect them. A large mass was removed surgically and 4 other small metastases were treated by gamma knife radiosurgery. Six weeks after radiosurgery, the 4 lesions had disappeared on MRI. We emphasise the importance of early diagnosis using MRI and treatment by radiosurgery for this rare condition.

Gradually Progressive Symptoms of Normal Pressure Hydrocephalus Caused by an Arachnoid Cyst in the Fourth Ventricle: a Case Report

BACKGROUND Arachnoid cysts in the fourth ventricle are extremely rare, with only 13 cases having been described in the literature. Especially, only 1 case of a patient older than 70 years has been reported. Arachnoid cysts in the fourth ventricle may cause obstructive hydrocephalus. Here, we report the case of a 72-year-old man who presented with an arachnoid cyst in the fourth ventricle that caused gradually progressive symptoms of normal pressure hydrocephalus. METHODS A 72-year-old man complaining of persistent dizziness and gait difficulty was admitted to our hospital due to a gradual worsening of his symptoms and apparent cognitive impairment. Computed tomography scan of the head showed symmetrically dilated third, fourth, and lateral ventricles. RESULT Though we performed a ventriculoperitoneal shunt operation, his trunk ataxia persisted. We finally diagnosed an arachnoid cyst in the fourth ventricle by direct ventricular infusion of enhanced material. We performed direct surgical fenestration of the cyst and achieved a good outcome. CONCLUSION Arachnoid cysts of the fourth ventricle are exceedingly rare, but it is important to recognize them because they cause normal pressure hydrocephalus symptoms and cerebellar or brainstem deficit. We propose detailed neurologic and radiologic examinations of patients with normal pressure hydrocephalus symptoms to avoid unnecessary shunt.

Colour Doppler flow imaging of the superior ophthalmic vein in dural arteriovenous fistulas before and after surgery.

The aim of this study was to examine the clinical significance of the colour Doppler flow imaging (CDFI) findings of the superior ophthalmic vein (SOV) in intracranial dural arteriovenous fistulas (DAVF). The SOV was examined by CDFI in 12 cases of DAVF before and after surgery. Before surgery, the average SOV diameter was 3.57+/-1.18 mm (mean +/- standard deviation, which was significantly wide (P<0.05) compared with the control value. One case showed reversed flow. Four cases showed an abnormal waveform. The cases with the more severe clinical symptoms showed wider SOV diameters and more abnormal waveforms than those with mild clinical symptoms. Postoperatively, the mean SOV diameter and mean resistance index improved significantly (P< 0.05); the flow direction and waveform became normal in each. The SOV CDFI findings were found to be useful as screening and follow-up techniques for the intracranial DAVFs.